Add recurring transaction detection, subscriptions page, and UK tax reporting

- Recurring service: auto-detects direct debits/subscriptions from CSV imports
  using frequency analysis; manual toggle in transaction detail drawer
- Subscriptions page (/subscriptions): groups recurring payments with monthly
  cost equivalents, next-payment badges, and re-scan trigger
- UK Tax page (/tax): payslips/P60 entry, income tax + NI + CGT + dividend tax
  calculations, configurable rate tables per tax year (pre-seeded 2024/25 and
  2025/26), editable in-app so Budget changes need no rebuild
- Migration 0006: tax_rate_configs, tax_profiles, payslips, manual_cgt_disposals
  with RLS; seeds 2025/2026 rate configs for existing users
- Chart tooltip fix: all Recharts tooltips now use TOOLTIP_STYLE constant so
  they render correctly across all dark/light themes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/eslint.config.js

@@ -0,0 +1,30 @@
+import tseslint from "@typescript-eslint/eslint-plugin";
+import tsParser from "@typescript-eslint/parser";
+import reactHooks from "eslint-plugin-react-hooks";
+
+export default [
+  {
+    ignores: ["dist/**", "node_modules/**"],
+  },
+  {
+    files: ["src/**/*.{ts,tsx}"],
+    languageOptions: {
+      parser: tsParser,
+      parserOptions: {
+        ecmaVersion: "latest",
+        sourceType: "module",
+        ecmaFeatures: { jsx: true },
+      },
+    },
+    plugins: {
+      "@typescript-eslint": tseslint,
+      "react-hooks": reactHooks,
+    },
+    rules: {
+      ...tseslint.configs.recommended.rules,
+      ...reactHooks.configs.recommended.rules,
+      "@typescript-eslint/no-unused-vars": ["warn", { argsIgnorePattern: "^_", varsIgnorePattern: "^_" }],
+      "@typescript-eslint/no-explicit-any": "warn",
+    },
+  },
+];